Pneumatically-filled fountain pen



Dec. 15, 1959 E. I. WESTMORELAND PNEUMATICALLY-FILLED FOUNTAIN PEN Filed Jan. 4, 1957 FIG. 4

FIG. 5

E. I. Westmore/and INVENTOR.

ATTORNEY PNEUMATlCALLY-FILLED FOUNTAIN PEN Edward I. Westmoreland, Plymouth, Mass.

Application January 4, 1957, Serial No. 632,462

1 Claim. (Cl. 120-47) This invention relates to a pneumatically-filled fountain pen of the type utilizing air pressure for collapsing the ink sac during the filling operation.

It has been proposed to collapse the ink sacs of fountain pens, preliminary to refilling, by air pressure developed in the barrel of the pen in various ways. For example, the patent to Carter, No. 1,893,579, shows the use of the cap as a pump by telescoping it over the end of the barrel, which is provided with a small aperture. A similar aperture is provided near the end of the cap, and by keeping a finger over this aperture while the cap is telescoped on the end of the barrel, the air thus confined in the cap is forced through the vent in the barrel to build up sufficient pressure in the barrel to collapse the sac, so that when the pressure is subse quently released, the sac will resume its normal position and thus draw ink into it. There are several objections to this arrangement. In the first place, if the user is not careful to firmly close the aperture of the cap, it is not possible to build up sufficient pressure to properly deflate the rubber sac. The proper use of the device thus requires more care and attention on the part of the users than they are always willing to give, and thus this principle has failed to find favor. A still more serious objection is that when the cap is removed from the point and placed on the end of the barrel, the hand of the user will often inadvertently cover the aperture unintentionally, and as the cap is placed upon the barrel, air pressure will thus be built up inside the barrel, and some of the ink will be expelled, with oftimes disastrous results. A pen of this type therefore requires extreme care on the part of the user, and therefore is not suitable for ordinary use.

It is a primary object of the present invention to provide a pneumatically filled fountain pen using the cap to build up a sac-collapsing pressure in the barrel of the pen which is not subject to the above objections.

A related object is to provide a fool-proof pen of the above type which is simple and inexpensive in construction, and which has the advantages of a pneumaticallyfilled pen in providing for complete collapse of the sac without the use of a lever mechanism and with a minimum of parts.

Still another object is to provide a fountain pen of the above type which requires no special manipulative skill on the part of the user to fill it, and which completely collapses the rubber sac so that upon expanding it can be completely filled with ink, thus providing a greater capacity than is possible with a lever-type filling mechanism.

The specific nature of my invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawing, in which:

Fig. l is a longitudinal view of a preferred form of the invention, partly in section, without the cap;

Fig. 2 is a longitudinal view of the cap of the pen in Fig. 1;

nited States Patent O Fig. 3 is a longitudinal view partly in section of the body portion of an alternative form of pen according to the invention;

Fig. 4 is a longitudinal view of a cap for the pen of Fig. 3; and

Fig. 5 is an enlarged view of the vent mechanism of the pen of Fig. 3 in the open position.

The writing end of the pen may be of a standard construction as shown in Fig. l, and comprises the usual point 2 held in feed tube 3 terminating in a sac-engaging nipple 4 and externally threaded at 6 to engage in a correspondingly threaded portion at the end of barrel 7 of the pen. The usual collapsible rubber sac S is fitted over nipple 4 and lies within the hollow portion of barrel 7. The opposite end of barrel 7 terminates in a small aperture 9, providing the only access to the atmosphere from the interior of the barrel. Near the end of the barrel an annular groove 12 is provided for retaining a standard O-ring 13 which has, when seated in its groove 12, a slightly greater diameter than that of barrel '7. A small protruding boss or stud 14 is provided on barrel 7 at a suitable distance from its end, for a purpose which will be explained below.

The cap of the pen shown in Fig. 1 is shown in Fig. 2, and is preferably made of metal for rigidity, although a suitably rigid plastic or other material may also be used if desired. The internal diameter of cap 16 is preferably made only slightly larger than the outside diameter of barrel 7, so that it can slide freely on barrel 7, but is slightly smaller than the outside diameter of O-ring 13. Cap 16 is provided at its open end with a tortuous slot 17 having a short longitudinal portion 18, a short circumferential portion 19, a relatively long longitudinal portion 21, and another short circumferential portion 22.

The diameter of the front end of barrel 7 is made slightly greater than the internal diameter of cap 16, so that when the cap is placed upon the front end of the pen in the usual fashion, it will be retained by friction fit between the enlarged front end of the barrel 7 and the engaged end portion of the cap. The provision of a slotted portion provides the necessary elasticity and spring action for the required friction fit.

When it is desired to use the fountain pen for writing, the cap is removed from the point end and placed upon the far end of the barrel. When this is done, the stud 14 will ordinarily engage the bottom edge 17 of the cap or, if the short straight portion 18 of the slot happens to be in alignment with the stud 14, then the ,cap may go on a little further until the stud engages the short circumferential portion 19, but unless the cap is deliberately rotated so that the stud 14 reaches long straight portion 21 of the slot, the cap will go no further. In this position, it will be seen that the slot 21 and 22 extends beyond the end of the barrel 7, so that the interior portion of the cap 16 is vented to the outside atmosphere, and no pressure can be built up inside the cap. However, if it is desired to fill the fountain pen, then the cap will be given the slight rotation necessary to align stud 14 with portion 21 of the slot. In this position, the cap can be pushed still further down. As soon as the cap is pushed down sufiiciently so that the slot is entirely below O-ring 13, the remaining portion of the cap interior is now sealed from the outside atmosphere, and as the cap is pushed still further onto the barrel, the air pressure in the cap can be vented only through aperture 9, and thus will build up a pressure inside of barrel 7 which will cause the sac 8 to collapse in known fashion. This, of course, expels all of the air from the sac, and, if the point is now dipped in ink, when the cap is subsequently withdrawn to the normal operating position, the sac will now be filled with ink and ready for writing. It will be noted that in all subsequent uses of the cap, until it is desired to again refill the sac with ink, the stud 14 will prevent accidental expulsion of ink from the sac.

It will thus be seen that the above construction com- :plics with all of the objects of the invention. It is not necessary for the userto place his finger over a vent, and accidental expulsion of ink from the sac by placing the cap on the end of the barrel is impossible, without deliberate manipulation by the user, due to the simple provision of stud 14 and the tortuous path of the slot 17. At the same time, the advantages of the pneumatic filling are obtained which insures the more complete collapse of the rubber sac than is otherwise possible, and consequently a greater ink supply is provided at each filling. The only extra parts required are the provision of a simple stud 14, and the O-ring 13, which is commercially available and which is known to be extremely durable in use, but which can be easily replaced when required.

Figs. 3 and 4 show an alternative construction providing essentially the same advantages but in a somewhat different form. In this case, a closable vent is provided at the far end of barrel '7', as is shown in detail in Fig. 5. A screw cap 29 having a flat bottom surface 3%] and a threaded stem portion 31 is threadedly fitted into the end portion of barrel '7. The screw portion 31 is preferably enlarged at 32. to prevent the cap from being entirely withdrawn and so lost. An aperture 33 is drilled into the screw 31 to provide access of air into the interior of barrel 7' when the screw is in the withdrawn position as shown in Fig. 5. The top of barrel 7 may be provided with a channel 35 in which is seated a small O-ring 36, so that when the cap 29 is screwed down, its bottom surface 30 will engage O-ring 36 to provide an air-tightseal. The top surface of cap screw 29 may be grooved or knurled as indicated at 37 to facilitate finger rotation of the cap screw. Although the same cap may be used for this pen as is shown in Fig. 2, and a stud similar to stud 14 may be provided if desired, it is preferred for this embodiment to use a simpler cap as shown in Fig. 4, provided only with a straight slot 17, which need extend only for a sufiicient length to ensure proper spring action to provide friction engagement of the end {of the cap with the barrel, and also to provide a vent to the outside until the cap is pushed sufliciently far down on the barrel for the purpose of filling.

During normal operation, the sealing cap 29 is screwed down so that there is no communication between the interior of barrel 7' and the atmosphere. However, when it is desired to till the pen, cap 29 is unscrewed to the position shown in Fig. 5, and cap 16 is pushed sufficiently far down over the end of the barre-l to collapse the rubber sac as before, and thus permit the pen to be filled. After the cap is withdrawn, screw 29 is turned back into the sealed position and there is no further danger of accidentally expelling fluid from the pen.

It will be apparent that the sealing arrangement of Fig. may be used with the embodiment of Fig. 1 to provide an additional safety factor if desired, although either modification by itself fulfills the major objects of the invention with regard to safety and simplicity of construction. It will also be apparent that the slot 17 could be omitted and only the aperture at the end of the slot retained, the cap being fastened to the point end by conventional screw-threading or in any other known manner, the purpose of the slot 17' in Fig. 4 being only to provide spring tension. One such cap-retaining means :is shown by way of example in Fig. 3 and comprises an O-ring 33 of slightly larger outside diameter than the inside diameter of the cap, to serve as a friction retaining means for the cap, in which case the lower portion of slot 17 may be omitted if desired and only a vent near the upper end of the slot be retained. However, if the O-ring 38 is used, it should be vented, e.g., by a shallow groove 4% extending beneath it, to prevent build-up of pressure when the cap is seated on the point end of the barrel.

It will thus be apparent that the embodiments shown are only exemplary and that various modifications can be made in construction and arrangement within the scope of my invention as defined in the appended claim.

I Claim:

A fountain pen comprising a barrel, a resilient ink sac iin said barrel, a point at one end of said barrel, a feed tube connecting said point and said ink sac, a protective cap for said point, said cap being telescopically fittable on the opp rite end of the barrel from the point when the pen is use, air seal means between said opposite end of the barrel and said cap for building up air pressure in said barrel to collapse said sac as the cap is telescopically compressed on said opposite end of the barrel, said cap having a closure at one end thereof, aperture means in the side of said cap intermediate its ends for providing, access of air to the interior of said cap when it is fitted for only a portion of its length over said sealing means, said cap being slidable on said opposite end of the barrel to a point where said aperture passes beyond said sealing means so that continued sliding motion of said cap builds up air pressure in said barrel to collapse the sac, said cap being siit from the front end thereof to a point intermediate the ends whereby the front end serves as a resilient barrel engaging point and the rear end as a pressure pump portion when the cap is slid over the rear end of the barrel, and a stud protruding from the exterior surface of said barrel at a distance from said opposite end thereof slightly less than the axial length of said slit and of less diameter than the Width of said slit, said slit having at least one abrupt bend near the open end of the cap for engaging said stud in said slit.

References Cited in the file of this patent UNITED STATES PATENTS 1,030,502 Carter June 25, 1912 1,346,184 Dickinson July 13, 1920 2,027,656 Tassie Jan. 14, 1936 FOREIGN PATENTS 9,634 Great Britain 1902 425,174 Italy Sept. 13, 1947 724,825 Great Britain Feb. 23, 1955 

